This nonprovisional application claims priority under 35 U.S.C. xc2xa7119(a) on U.S. patent application Ser. No. 2001-328106 and 2001-371813 filed in JAPAN on Oct. 25, 2001 and Dec. 5, 2001, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a sheet member with a heater wire suitable for use in an electric blanket, an electric bed sheet, an electric potential mat or the like, an electric potential mat using the same, and a method for fabricating the sheet member with a heater wire.
2. Description of the Prior Art
A sheet member with a heater wire, in which a heater wire for generating heat is fixed to the sheet member in a meandering shape, is used in, for example, an electric blanket, an electric bed sheet, an electric potential mat or the like. There has been known a sheet member with a heater wire in which a heater wire b is contained inside a sheet member xe2x80x9caxe2x80x9d obtained by superimposing two sheets of rectangular cloth members a1 and a2 one on another, as shown in, for example, FIG. 21. Each of the cloth members a1 and a2 includes a joint portion c, at which dotted portions are bonded or sewn to each other. Between the joint portions c and c is formed a wire passing portion d, into which the heater wire b is inserted. The heater wire b is positioned at a predetermined position by the use of the wire passing portion d.
However, since the two sheets of rectangular cloth members a1 and a2 are stuck to each other in the above-described sheet member with the heater wire, there arise problems of complicated structure, degraded productivity and a high material cost. Furthermore, in the prior art, there has been needed a work that the two sheets of rectangular cloth members a1 and a2 are stuck to each other in advance, thereby forming the sheet member xe2x80x9caxe2x80x9d, and then, the heater wire b is manually inserted into the wire passing portion d in sequence, resulting in poor productivity.
The present invention has been accomplished in an attempt to solve the above problems observed in the prior art. An object of the present invention is to provide a sheet member with a heater wire, in which the structure can be simplified and the productivity can be improved. Furthermore, another object of the present invention is to provide a method for fabricating the sheet member with a heater wire, in which the productivity can be improved. Moreover, a further object of the present invention is to provide an inexpensive electric potential mat by the use of the above-described sheet member with a heater wire.
According to a first aspect of the present invention, a sheet member with a heater wire comprising a sheet-like base cloth and a cylindrical containing portion containing the heater wire therein and attached at one surface of the base cloth in a meandering shape. Furthermore, it is desirable that the containing portion should be formed by folding a belt-shaped member in two along an axial line in its longitudinal direction so as to allow both side edges thereof to face to each other, and sewing the belt-shaped member in the vicinities of the side edges facing to each other integrally with the base cloth. Moreover, it is desirable that the base cloth should have a marking along the attaching position of the containing portion.
Additionally, it is desirable to constitute a electric potential mat using the sheet member with the heater wire and an electric potential generator for applying high voltage minus electric potential to human body insulated from the ground lying thereon. It is desirable that a mat body of the electric potential mat should be integrally provided with a controller section including an electric potential control circuit for controlling the electric potential generator and a switch for operating the electric potential control circuit so as to switch electric potential emission. The controller section may include a heater control circuit capable of controlling the heat generation by the heater wire, and a switch for operating the heater control circuit.
According to an another aspect of the present invention, a method for fabricating a sheet member with a heater wire comprises the steps of continuously supplying a containing member containing therein the heater wire and sewing the supplied containing member to one surface of a sheet-like base cloth in a meandering shape. Furthermore, it is desirable that the containing member should contain a heater wire therein by folding a belt-shaped member in two along an axial line in its longitudinal direction. Moreover, it is desirable that the containing member should be continuously supplied in the supplying step by using a containing jig having a belt-shaped member folding guide for folding the belt-shaped member in two as the belt-shaped member passes and a heater wire guide for guiding the heater wire in such a manner that the heater wire can be contained in the belt-shaped member folded in two. Additionally, it is desirable that the sewing step should be carried out by a sewing machine having a pressing metal fitting for pressing between a sewing section for sewing the containing member to the base cloth and the heater wire contained in the containing member, so as to prevent movement of the heater wire toward the sewing section. In addition, it is desirable that the containing member should be sewn in accordance with a marking previously formed at a containing member attaching position of the base cloth in the sewing step.